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Which electrode for which application? Direct pH measurement.

You are here:   Metrohm USA   >>   Support   >>   FAQs   >>   Electrodes - Comparison Chart


 

Application

Specifics

Electrode description*

Cat.No./Order No.

Reference Electrolyte

Remarks

Water

water with low conductivity

Aquatrode - combined LL pH glass electrode

020910623
(6.0252.100)

c(KCI) = 3 mol/L

020096101
(6.2308.020)

Store the Aquatrode in c(KCI) = 3 mol/L and condition it by immersing in the sample before measuring

water with high conductivity, sea water

combined pH glass electrode, ground-joint diaphragm, double junction

020910500
(6.0219.100)

c(KCl) = 3 mol/L

020096101
(6.2308.020)

electrode available in different lengths

waste water

 

 

for simultaneous temperature measurement

combined pH glass electrode, ground-joint diaphragm, double junction

Unitrode - LL combined pH electrode, Pt 1000 temperature sensor, fixed cable

020910500
(6.0219.100)

 

 

020910658
(6.0228.000)

c(KCl) = 3 mol/L

020096101
(6.2308.020)

electrode available in different lengths

Colors, Dyes

   

Unitrode - LL combined pH electrode, Pt 1000, fixed cable

020910658
(6.0258.000)

c(KCl) = 3 mol/L

020096101
(6.2308.020)

electrode available in different lengths

Electroplating baths

   

Unitrode - LL combined pH electrode, Pt 1000, fixed cable

 

020910658
(6.0258.000)

c(KCl) = 3 mol/L

020096101
(6.2308.020)

electrode available in different lengths

Polymers, resins

   

Unitrode - LL combined pH electrode, Pt 1000, fixed cable

020910658
(6.0258.000)

c(KCl) = 3 mol/L

020096101
(6.2308.020)

 

or Idrolyte1 fpr T>80°C

020095059
(6.2308.040)

the choice of electrolyte depends on the composition of the sample. The electrolyte solution must not precipitate the sample.

 

Food

beer and milk

Porotrode - LL Porotrode

020912308
(6.0235.100)

Porolyte2

020095954
(6.2318.000)

Can be regenerated with pepsin solutiion3.

wine, fruit and vegetable juice

 

Unitrode - LL combined pH electrode, Pt 1000, fixed cable

020910658
(6.0258.000)

c(KCl) = 3 mol/L

020096101
(6.2308.020)

 

dairy products: butter, cream, yoghurt

 

Spearhead electrode - LL combined pH penetration glass electrode, polymer electrolyte

020912316
(6.0226.100)

Not refillable

The 6.0226.100 spearhead electrode should be regularly rinsed with alcohol to remove the fat residues from the sample. When regenerating the electrode with pepsin solution3 make sure only the membrane - not the diaphragm - is immersed into the solution.

meat and cheese, penetration measurements

 

fruit and vegetables, penetration measurements

Combined LL pH glass electrode, spearhead

020912201
(6.0236.100)

c(KCl) = 3 mol/L

020096101
(6.2308.020)

 

Cosmetics, detergents

   

Combined LL pH glass electrode

020910607
(6.0239.100)

c(KCl) = 3 mol/L

020096101
(6.2308.020)

Electrode is also available with a plug-in head S:
020910615
(6.0239.500)4

Soil

 

Combined flat membrane pH glass electrode

020915617
(6.0227.100)

c(KCl) = 3 mol/L

020096101
(6.2308.020)

If measuring on field use a penetration electrode 020912316
(6.0226.100)

Biology

small sample volume

Combined LL micro pH glass electrode

020910739
(6.0224.100)

Idrolyte1

02009505-9
(6.2308.040)

Shaft diameter 3 mm. Also available with ceramic diaphragm and 3mol/L KCI, order no: 6.9902.074

Measurement on surfaces

paper industry, skin, leather

Combined flat membrane pH glass electrode

020915617
(6.0227.100)

c(KCl) = 3 mol/L

020096101
(6.2308.020)

This electrode is also very handy for titrations in small sample volumes: immersion depth: 1–2 mm

* With the exception of 6.0258.000, all these electrodes are equipped with a Metrohm plug-in head G4

1 Idrolyte is a glycerine based electrolyte solution where the activity of chloride ions is equal to the chloride activity in a 3 mol/L KCl solution. This means that the 3 mol/L KCl solution can be replaced by Idrolyte without problems. Idrolyte is the ideal electrolyte for protein containing solutions and partly non aqueous media.

2 Porolyte is a polymerized KCI solution and is used in electrodes with a capillary diaphragm like the Porotrode.

3 See the leaflet that accompanies each Metrosensor pH electrode.

4 To connect an electrode with plug-in head G to a Metrohm 691, 692, 704, 713 or 744, Titrino or 726/796 Titroprocessor, use one of the following cables: 6.2104.020 (1 m), 6.2104.030 (2 m) or 6.2104.040 (3 m); to connect an electrode with plug-in head S to the above instruments, use cable 6.2104.510 (1 m). See Metrosensor Electrode Catalog for additonal information.